SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '03c44fb17fc1f92c1898daa1281604ee4a4cbbf10a16df130f481e31d393c6d5' 
  AND token = 'xaEtxzxYTvcTg5S0tVIch8m5gIlp98mMnwghRtYnXVg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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