SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0f7a6fcf7a75a26e1f169011950b1f03f016e6f42b54e7877171127379971247' 
  AND token = 'M2CB8UH6FE9iVHz0rF6lIgnoi4PwaByvnjeMWa+llD8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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