SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9889d0667e721fd5980c3c2ad860a423c484754a380c9cec6e8c98c07e5def14' 
  AND token = 'q4RK7NDvNfQ/efK088gdDdjkuoq4xlBjjDZ9PrXPmro=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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