SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '6a5a20abc6ab710ccd77d1f7df30855563dbf67fbdb60a37824e276b9824438d' 
  AND token = '1UGVlnNClKklzbTLD7bKnwcm4O/xZfHW/WuOh265sXI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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