SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '767a4196d66fab3d56bdb9443d2b46c49aa3c3b635b9c1056f1e67d50448bef1' 
  AND token = 'UCuzKMk/iiYoCqn83/HrNSc7eDsIztR7SgCTyhvibg0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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