SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'daacf0f8fd6d6f90d98be0ebe04544fc405bda9b7f4c0be373928a4bd51bfa1a' 
  AND token = 'nd8xjUtGr2IOAdUryQzIUDyckj38dgTkIKVZ5BwatiU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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