SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9850de45fb3b3e938798b5ce1092d40f693fd2804a54a11b7219a9ef85b24367' 
  AND token = '4m3PvMUQ9ehHRSjgRbKktFju9r3vmS+7yOofzBKTZhA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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