SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f38cae5c8f2b525bde1afc8dfecc4bfad9f4b357553917f05e74a47dd88a63c5' 
  AND token = 'TBRAiYobjCnNLEa+DlOyz4R/l4+984wGCPsziCEWp8E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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