SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '30eb72836700a26133e9bd3795b3db0b15f805f3c1be1645d95587112ee849f2' 
  AND token = 'BKUJPxGxUa1BOcPLpGBDeaADliMJy3EYumq7LjiLgbk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}