SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '2b6cb08d120cf441141a6cd99c6b7073ae8d48833924e41b1fd4076c385b2bf7' 
  AND token = 'WCp+UeWDVwIIjj1mAD7lAWG9L+c75MGR0/RgNTBBb0M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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