SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3051ee09e7632f8e830ac2ad44c219f7ca100e5e1367751b4e5d654590638f33' 
  AND token = 'YcHWTxF8BVOdQLs5VAt9FBDOIUoZNwfinZFL/XAVr3o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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