SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'df372d7fd669d230590234e77bca1474db6c5c66fdda71ae4fd52e158c4c8ac6' 
  AND token = 'klDLv9Va1R6QxXRnlR402N3bG1ywZsFCnyuy1HeHv0U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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