SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'cfa69794cf8735e65227550595704bac179edb68bb4e9ec39115afc873996958' 
  AND token = 'mbKjj7BBipykjmbVum+GEh+RoFqrwGfYSrhFmmfImF8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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