SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2d6b37e941a8018b5bdbc12113d666de556ceb4da4c30d10730072705cfec201' 
  AND token = 'xGQT5xIiuxV5JYogkGKpUvNBOag2kBJKA8ZtOf3odmA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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