SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4c8530923cf052eac6f20d5d52f625afed1381004c379592c2851500b0f68764' 
  AND token = 'drrHUS/JEqKUbAAmNwVqGLmZL7GUFTuu0NDNVNXYA9c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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