SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '31c1752799e8d92d3ca4b9c782adf3b69a591ec31db5f7f971cb3b71372bcc9c' 
  AND token = 'xzZ098QKnAWq4r7Ova3qwYCBqxYnYNwGwhIyzfRfsDU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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