SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4e978a6119d5ccf43a7f091940ee9f089d2d62811dbe7cfe7910c4d1d32009ca' 
  AND token = 'AnXg/ExZHWUOerlC8dnHPTTmIEA2AvIMtNmaVX1hgIU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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