SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b1bfcdc9642fd068f82ae414919168caf68bae7658068060909c7421e5bb637e' 
  AND token = '7Mj8zJL+w33S9hHYxXvXuRrVl57g3WpOcxSByiw5R8A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}