SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e3403925147a0ea2055ffc44a4396c7a6406533563f4eccd3cf7f60ffcebfde3' 
  AND token = '3HD1sBwqZ/jhWZJNIcaUPFjqIKsJKc9JW/BvayqNNwc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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