SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f6830e962fe5b7ef9589b6b1b71c71df85ec8e4274cd6ef09a9480db36b4650a' 
  AND token = 'rtVGHI4hD4GEsOG3O+oEgEZI0fMp5bqVzVKdKdgqYZo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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