SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '31104499d9ffd19d5010b80f382830712d2527d6d155e743006c3ba19cc2c845' 
  AND token = 'GliuCvrlISEc6bBLON95mm8PVvDwCoqaX5WdM05AWD4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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