SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6793468dd038aee908e8763be54d5c230f7de3b2d8e2bc2c49552a3f5f06c841' 
  AND token = 'g8Bh+hfSQdsItBSsavPq/pj2xcTUxbYTqs3wqprBlgs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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