SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '44e6843c69341eaa577a40b7e984e79b16dda7dfba259428e1e175fcadef0ea3' 
  AND token = '4FyEePRWr5ifdNQ4VwJrfeFprZC9uyQxVBhDK/tJ8KQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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