SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2a8f04b5c2ca441530298d3a96eddabaa03b8eaa4db666378dcdc975f79726be' 
  AND token = 'MbaoD45Gy8Wwh6aRgtXYLKk/yqflyGBanAhbfWGCZ/0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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