SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '89e0dbc2386f0e75bb5a0c2a101a2b8fc22ca8fc15ca90157283981ea0dc442d' 
  AND token = 'UBOlqKGw3E6EZ3GfeG7uPoYyL28z2nNC5+/MldiVueM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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