SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a552d083523a0dabf6eabf8ecf3dc271e1964422f62b9c68e86ec25d0ffdfad2' 
  AND token = 'xrdUwrSRndlgwfcW7DnGITvO0YEjJXOUHqGq0tkVNcg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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