SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '86960a54a55c1f25b8be9e951eb4cca14def44d46b8fab4b5d4a53e1f83a0203' 
  AND token = 'yAW1ZhnCkrWB0/QLGzvGp/sDtJLVXq7036Ss4qKQQ0Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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