SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a57fd1ff8d56ef24063e2ea9884b6923d03c92991690bac01246e07077f6f9a7' 
  AND token = 'JfO+eVo9I/GFOH4UJHuaSvWjXNPWYgDZb08Yay7r2GU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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