SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a96c9ed95275b5c3b93185fe56bf9cef159f2f0f3b6ec646b56c3206978f6117' 
  AND token = 'ZXetdSb9FV3OzHs8njriZFYqvWOcRQIc1kVBzsCugrA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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