SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ae916eff9b1b6c3280a65cb85f1dd5176c8e2ac08358be6e47a1df5f2cfd80f4' 
  AND token = 'igIo+ldDx1o5q++a+YDRLNlXHmynUSU435ld40+0Osg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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