SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '589c1ac339f6858234d073f6f52a1f5902d6ab671f60316b56458eb89d506171' 
  AND token = 'yoRazL3sRJg0/Tt06oYA/AMQDdq847PQu3fAq7YuZ4s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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