SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4ff0dd530922c517cc40256428f602d8c1013f3cef42597f1619ab56af5fc6b0' 
  AND token = 'izGOfKwPuNKI03UVzkXd7KM+UnwzNwg4nPD9gE+OqUo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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