SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8efddcfdaa4826266af7b6c0a54fd23c51a0746c0b6b73a6f7553d8deb7aad29' 
  AND token = 'hnax9i2IM1B24AFWyTLOLT4WfgP7R5cCLiptuo/P0RU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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