SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7e89e847f4f505ed7a8e632f46eb0bf10d1e744393e5333742b774f6ec34c83d' 
  AND token = 'lAtQxfTQAwuYUpqhdsU93U1LbVeC6uUSgC+hy99Mias=' 
  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"
    }
  }
}