SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0319d606d54abbef627e5343a538ba15b609338f6a6db861d430de5ca44493b8' 
  AND token = 'KK/IhPAcbUA+3ogTolAtVqZYe935opfJluTy++XAlFI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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