SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0dff08867a751919d155f6296f88ab8cece626c4879b014cd46d0b4e2846be67' 
  AND token = 'q5ckixHj96HD+SVTb5kJxEktBNTeP5uPlOzOSL+gHto=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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