SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '904ecdaf0e5a33832ccb418c0cb7e70ce8bef42491509222e66c7d18b6fb42e0' 
  AND token = '1ePt+yxWzdRUETneZYtiM8EeGCBdfMUOoAsz+5ZJPbQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}