SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c7a54da565e41417b894ee68127e1397e814f16ff5556424296af8371256005a' 
  AND token = 't3j5HRSqV7Zy/9NW3bSl0ubwCpJQWg51GElaKB6pfQM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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