SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5781fb35b238bfa7fc6899c03fe6ef73dfb2e807a32d6cf9b4441b5ebb74039c' 
  AND token = 'xh77tCwhHF0wODaNenD3gF6Fky80naAFc1Bgsh5YiNg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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