SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '97c712f4c806f1f8b7f5a8d6b8f95f577d1375dd25af909e7318be04dcb3216d' 
  AND token = 'vXC8vL8JpFUuZ+5/mvYLmDQTxZ/66ijveesvnYDJBT8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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