SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '67047e1a39cfba78f02a13bf1631b5c87b667455d93ebf3176d2d55818e8832c' 
  AND token = 'AznIiXyVARYXV3HhcULE3b9ZFJ1mW0WqofydcL1UPKc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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