SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7dcbde1b3d0aaa58a432cda52acb82a20433690c6d807999587e12f959136d6d' 
  AND token = 'VJCTECgitmaDB9BbmXIjpjzxg4Uq3JrvnZLrOwLA9XI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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