SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd5321db31bae285f9bbfed400a86785c1dcb6b9728710d71cf612d65458b2555' 
  AND token = 'qpPlCgrMn+QxuYYvyHG+Y6Fz+pkuhmQ5dWowIpjHaFA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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