SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'd471f7f3d9af451dafa6496babdee17edb5b7dc1ec1b42b096156ac3bf9bd8d2' 
  AND token = 'FSaKKfwP/WNLwhBBHZzRCS2TDP5Aw+B56++9uK+T0pI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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