SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd6af4cfec5c38dbb4c617d97b5e897764616cb5bfc51868903272c17ba068c05' 
  AND token = 'mj46oCjoACsQS00QCUV+uLthr5QmHj1bWClRb0MyZS0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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