SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '3ac5b509615ad7d81f0930dcc4a4d21f00c0c5f8b3548d6a952e28a4e2b44254' 
  AND token = 'SMnupqjChAJaochsVFHgBWB3CsKEfm6g36LctM31mDk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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