SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '285983b7a08f36712bd6123498949b8b015f4cd4a5a35247ffd721a966329159' 
  AND token = 'jmNCSck00hOnOB8RbzbaC+5NShbE6ywPhNuQ2BR4N7w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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