SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '448241d19f69c9893dafe53af71b41204f9902537a7c15649a2e1e9935b2e803' 
  AND token = 'N9A4pM1t3416zCvvLYMmg+OJ4fBnF0/gjlTHipVRqOk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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