SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5c4bcece9fecac3e73c0a7c6aba67437a66079fae91233d44459ebbc564e96b6' 
  AND token = 'ddUttYCwi++PfY4ACS6KIFTexiqdum6GABg6QcVDDLE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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