SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f3f444cefc62cdb355223f157adc5c87c8382871f86cb23be24af6bc0a18f9fd' 
  AND token = 'dj4dEz3xKbTfGs2hIzi8KcJSu5hOjKGJ0vTJ6n9aa9k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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