SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0284755ca79ccfa2cf3d08c86cf7bd3832c261b6b89c6941934b63cfa120d218' 
  AND token = 'EBPC3AwdS7IuW5USjA4W7tM3UfavpsduxjWqd323++U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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