SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '85d67ba12edaf5daecb98a7180824a2a5adf9b97d918af6dc384a6fec5b89376' 
  AND token = 'Qb2bl3xqkO95FZWcHn8MWDmpS32SdMfEumjQd8LWXcw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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