SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '43f28d9cb83694c6783fc97586748f652733a18e92be84b11c22a915aa7ce4a7' 
  AND token = 'GuXh9jm7qe0/U7zMlsu88ghWf9iKmWCuvsnGPqd6xmI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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