SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '395f96310df0860619ca56d4974cb90cffb938ef62efb253a98546ddb39c74f7' 
  AND token = 'mFvi2WtknYqDPRHWAZDeTvHj+yQrm5piGT4eEfV7eLk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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