SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b4fbfb3de4311d78befd2a4b477281fd9f0edeac7cbb09656c25d3b836b1516f' 
  AND token = 'R6lkZb54xE+/H7IRV8qIx6vziPydiqfQIgGvUymk5ZE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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