SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9c167a8754212569fd26223157f5fdea6342af05d2834c448d9cd4c2d0cbc10c' 
  AND token = '3AKCgWsScd15oH7BdU1hbyLc904cgbcGSLBgVH/oqns=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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