SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '935ae4906ab140f3d68034ab39356df863f6d00eed2e57157eef7742396ef425' 
  AND token = 'OqisWZgC2m+KQGMlUQCn3GvVo9TU0GLuEML1RwCXYs4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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