SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '16574018028904db523dc12344a02374f553d7d81e13b1fcdc5cbc9390480c32' 
  AND token = '1Mjcl37Be9Dmed7xNwmmRT9ghAgfM9GstJ02tNCcmh8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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