SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '60209518f23f747006ecc96798142e3355b4bcef11a21635499353ef4dcffc84' 
  AND token = 'ZankuabLUOITPS+JYXHXD7MWkPwzE4WkartZvMCqFpo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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