SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2f10cf268da8f762fb717333316d3e814ba348deb534f115479b7e252fc78954' 
  AND token = 'KOMOD/rFYeth+Z0/f8JD7lJ/STFOfb3l7YYNwvkuVkk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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