SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '845962744e966b04a431577a339fb69af306914b7ab9df0ce9f2319e132070d4' 
  AND token = 'cIwHPipRoRPES7jGFKSvHqOzZGE488nXRvwW8vL35no=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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