SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'db1fd3ee1df4d3d4aa1bb88f32cb0780366ff416fb1a412183dd2594b5a1b9fc' 
  AND token = 'YijhGjzhTh82Sa5Du9cS3Q4qG7DCZOjx0VQ27BvKGuQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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