SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '49390923ffcaf6d1d8b6c25983538968c678570f70349db54b95e7ddb012e8ec' 
  AND token = 'hd8SSd06plfTqjNyb6Mm0VviGTgPKaPEWi6sCJfwCbc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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