SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4792c77df17f6483fedd59918df0070729741efebaf86b5a56eb530f48dc56e3' 
  AND token = 'uqmVTK2bYUr+eHo3lgzpEw9pSGIT4np7G5W3uFvOwSM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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