SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4bbc0a0f4a3a8a3f9f0cd98d6bf4f482974098a0ed8623d7c79d58ff18141f6f' 
  AND token = 'LwJeWvgZZT2xij8+ZRkVBpb9JTyVn+j3/IA5Qz40paw=' 
  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"
    }
  }
}