SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ddebcc397ba09a6362dfd26a78def954c37876df2c03ecec8d9b9897b8b4aa7c' 
  AND token = 'P48o89emTBfiTI4v7lfqcynOAc3155rnF+mSwR49DwA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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