SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f3114e02d9fe909e8302b0691355f74d376041f22b9bb271ed8f61bc2692b826' 
  AND token = 'WPq9pZsw7esAr0qxznixONKJGM31oUr52nVqVgpDfFo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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