SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'deef730f6b5876618557fdf632b087532c27a6638db99bc9771fb1cd5d25a376' 
  AND token = 'KFbgZPD0wvFaUKh/sbj8TufT9tp3NQp+yVNpWlDAgVs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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