SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5b0fbe84e97f738e9c71abb4437d45d1c89c8fdaf8c22277df9f418d276c6f3d' 
  AND token = '5xW+OhWM+qDcBhOMWvJCy/inffExKj29gZeis4HwnlY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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