SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ae8b455268c69b6370220e21162a93969c205299debbb4aecc554a971f8cdf3d' 
  AND token = 'fGII6Ljm0HSfji5JmHidKXtBBVgSL8i8Ye+Q3FADp50=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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