SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6889171433758945980379ca5e50011c095f84322cf4b64b9f54051d264708c2' 
  AND token = '+2AVEdpBOFJMJa3f4D0f6D3wQn8Uncsq6uKaxCyPwAA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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