SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8f8cd770de8247fadf58daf22f38715ed500595df453898dd4fe583aa21cfe09' 
  AND token = 'XVB9W2Or9Iqw7xsWYO8umSZ2UmY1olkv5xhkGVjqYDA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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