SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e366b75d32674399262f0ae1288d420a66d2ad398afc338fe0990ece3693d36e' 
  AND token = 'iUoRcUK0xLc8VHqkdgb4dSGGd1vhg6ts4+pwMONPhuM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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