SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '53cc408188c07df3cb434fe2a55c997735f167ebf42c57082ac6b5cc573f3560' 
  AND token = 'fTgpU8RqnYaE7BD0ZCUlUWY0ST9s8zUzx+ToLQCOHkc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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