SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'caec85761d77e276089285bc3e88dca4678cf402b96465444edb67832f5c237e' 
  AND token = '8/5MY9LwpsJbYcTwWTQBVXLI7JIH+jnu+js/xrOFfgo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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