SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '709b20f283205f2117c1b4246f5c82b7b39a0b24fa51bdb781ad46cd7354f808' 
  AND token = 'rIxgHMkCIJSjYOFHlOGka3gv17gLjOXwDnAcjGWGAHY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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