SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2a112a14399440ebde2dedc24c97d17d6313a144d629803a03c331808ecd1ac0' 
  AND token = 'o14mOdaProBbMCWy4ITPVAAxnowA5yIYQb2r3kaHWjU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}