SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '35f28f0fd6c0bb568922889f3b55b5e03437910454b59b5780750dee78d8be3d' 
  AND token = 'DGKM8GrKKYLiQaJUsuIwmiw+JwmvvJ6L0QjSxqjScuQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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