SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '63bb6b3267a3ebfaa63a0c90b99d1d837e1cd12d3e0dad55ce27efe4bade0279' 
  AND token = 'bJg0h7LPcKg7s94NDpiINrBVQ+rcP+XUMlYeyaHnky4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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