SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c184957e7a4e5a13efcf1c3ad2c4937e2988d026b4ce57f905cd186043073728' 
  AND token = 'zL+eVqV1wDzrDcIuWXLYlxeJE6LqOzqyH9uPszSs46I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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