SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0b14433cce645b365cf0fc5be17d10240e27f9b7da2523fdf412a28035788e49' 
  AND token = 'ncqy0i3NHK2yFd69BhyzXl71miCVEOtbjyYWfoYLMRM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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