SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5de25621b6e985b5de1860da955f9a750328cd863d81ad89bc118cbfddb9d9c0' 
  AND token = 'gxp8FzjOe7asCK05dc5QxIlmSS5VZdqudCSLAmIf/7Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}