SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6b7db2363e973d518f72c6cc50953dd7a3d6f8c62599585d927aee3a8041419a' 
  AND token = 'FzwrwihBqFIz5nQ9GvhJHEL/TEHaHOnfHupW7JRj8CE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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