SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fc520eb1ea5916542f98b980f9ca7fc9d5038d71ebc04fb8e1e6a4ccb3094227' 
  AND token = 'rBBxJl+QD64POzPsvtOEQjKRTOKyzCQREamXi5vd4Vo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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