SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '84044cc6d652119a859307dc54ce1509a3bcb63d847355ebde5b6b16142a15ed' 
  AND token = 'h/dk8wSR5gb2ZGaNmYrnDEAjyKiHSs4yhHIgEijqToQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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