SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6e02a52fe2298df7b71fc12c42c01252b190db38de1f7d5ddbdae5b9ac44bf22' 
  AND token = 'x7b5K4R1jud9W/gitSmT5T6tecJ50npltUFGKCZQM6A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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