SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fcb8a16e251e00c029f8da03cdf51bf0226c760860ca11d3b8407b35df31d757' 
  AND token = '8F/xwmJ8UCedGh87YKu7gFQ4zWC0+6sX6iV0GkPlFBs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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