SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7befb22557a03957adf0824dd3dce9dada4aaf2dc2376ed39bffce2e5235e6ee' 
  AND token = 'JqNrnETuIJq0DZ6dUdVkq78bR3BV6MeU3PWnQdxqe7g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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