SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1f26af261e7c528dbf337c1f8af196de7dcf76f9009a93f3f9b69bb63393a710' 
  AND token = 'YnoXVZ4nRF9yFKgWzl9IpuwaCTYmXAWt+xPwPsHCjf4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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