SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2421359da9cce30acdd5553af2ca9f1ca78b2960bf153b4936cfeac2192a82f3' 
  AND token = 'ay0tlBhHi/CzLUTM9WCOyggiYzOn4i90ujzjXZ9mJvc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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