SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '33cef3f34bd6a33a4a23a00eaaf2daf79ba494522c352a6b514dcde4e8ea8fa7' 
  AND token = 'gRqmL5BkWDgCcX+IuNWEaEeiCwACFl0M/nZik7lLPMo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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