SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a444756c2254063a94f7937690b83282bc58bd099cd3d63fa6d06e7b8446ec0d' 
  AND token = 'Qb4nDlFdJTuhmYCJReNfgImNuHqemOs3Vva5ZTvJ4dI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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