SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'de02da852280bbc2af2d70853f423054036bb79a0df782b7f93d1f1668998bb6' 
  AND token = 'tEG0WbYzUj/KNByYrJbH3BsnzZxBOxmwCXVeutQvfys=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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