SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '393c8e79c622af273c0000c777f033d066214d7b2b7497d69cf23f1cda9876c2' 
  AND token = 'Fw8Xs3awbMA+MkNHcvu2CVd6pxrEINwnajPpFu/oYmo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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