SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '596ea58408de56e88a2d2390ae8ba18f89b58adee8faadb623715ded91f259fd' 
  AND token = '2lBgZV66qqR8pOSoCCHxN8y+2uzxKongq1bhgP9U79k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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