SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'd629d1038de949567e04fae1e1e64490a3f6271a94504412a3cf00f5a881aead' 
  AND token = 'R1ZNppAqDzLKFf1ZaryBllXa7dXzdvEMz2WEGilj87c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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