SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8104df5a126b75ce3c5ba59df704c237ec82ed0c695374b5eb5fd7f6e5756674' 
  AND token = '0+DyrqULt0zm3Os4aS3UymaLwUyitcJQBGN+uxjNUAU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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