SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4c9985c77c548ace47c12ce9489b22cf35e224aa7dad1ef1743fef0ab3d5bc00' 
  AND token = 'X5FXtEEFHLFPNdq75oEM5udB01d9FTItqakmqIlNGTM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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