SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3aa651290ad08e68ddbfd30c6923c38a0cfa3f502a0c1087bcebd03c46983b34' 
  AND token = 'AlaiWMlHwi4pdFruYw8qkkXlaLW9j80GYKu8iqNKCgk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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