SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '74eba74e8f4f2fbac2369586f72c2b6bdf1b6c89d5e5060eb8a1c14056d632a3' 
  AND token = 'L2Cd/uYS3UlzDoyVW0SqfYgu+Flfd1lHFgErX3jYGto=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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