SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8e97674d4a2c38aaf1233f0636f2b1629a4d71a5fe6344a693382bca8c1cde93' 
  AND token = 'sQRm9lgCtmyLeCG25IRFBOy/ru5LEP1gTPYwBz1Eu7w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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