SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7d1c0ae11774700321dd7a1e38e9945aac04939086d372ec3dab22e9cdab8acf' 
  AND token = 'p8blxeIIM/b6mJb03N7OaiAd49GjCOnIkbumtTgali0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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