SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd5e9888b9b2b1f96a54d57e8939d3ddbe47eca758f061696f315adca4193f921' 
  AND token = 'KuMIxc8e5bqF8Pfd7NDHz808wsQlxoxqUnf1q8+HCQc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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