SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '2861a0a9b9775b7d7b9a10dcde5769046f4a4c1bbfb8fb7579311a9f0071d621' 
  AND token = 'ozRcXq0sZ0yksg3gvjEwjZuaFd6nHz+JbZhW4TY9av8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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