SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '03bb1e957476d64f9ed0628a08a4196602dbe2b49b02db05849a5882bf477dff' 
  AND token = 'hJ+aUJY+u6HWb4iCyMrWmIx6AQpc1voyusIYNLmDJN4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00011

JSON explain

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