SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4471ded4af38526567328452178edd09c8478bd5cb9ea16814d016293c793783' 
  AND token = '+At7Izgcq4A6jgBZEb1cZbKfgwS+s573nBpMqlYhSDE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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