SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1e850482d3f82f61837e752c8b1a96aec2d95e823fa6b4871fa3978c9bd8a186' 
  AND token = 'hocjc7+uoqzJPzwVPwZpWWjzjNa0GRyVySI1xpijl1c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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