SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a4f0c2db3a18b9ee7838c303cf9893526632c4655a7a0719db825520ddeb7ecb' 
  AND token = 'rp0JEeaNupf/8xHlACqQbhxDlNyf7pkPr2dYf88oamo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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