SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f371d79457dd98091a61c5fde9e724adb518a415cf8f8bc933c258554cc05215' 
  AND token = '1hZiIMB/mQZtwhvnT88sjeRkA5oraIypWC5ZVtRpt9Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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