SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd75abd7b4c8385576d6b0a4af14942acd2d5173f8897eab5ce95b9ae57e11d19' 
  AND token = 'vBADIejSpL6CswVKdtYmRwGtri1GSTFqKGjfTj/4unA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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