SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3577627702819cb16680d65b024234d70b4387e3278bf82f31816dafb0dc6652' 
  AND token = 'sMADVOvieVpqEwLX9X59s7As319eSV94+mmxuOOoZ3I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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