SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5c91364b467ebdaa656a3da1cb07f17540576c794895cf94c711a3563b360324' 
  AND token = 'rqz2pEyzL15/gDDNrE2J6hSRi9DosleJDPaEKxHoBnI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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