NOTE
MySQL Table Access Methods
Full scans, index scans, range access, point lookup, ref access, and plan-dependent row retrieval.
This is a historical learning note and may contain outdated or incomplete understanding.
A query plan can retrieve rows through a full table/index scan, point lookup, range scan, ref-style indexed lookup, or other optimizer-selected access methods. The type/access information in EXPLAIN is a clue, not a complete performance verdict.
Judge an access path together with estimated/actual rows, predicates, ordering, covering behavior, joins, and data distribution. A full scan can be correct for a small table or low-selectivity query.