SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5a40d17c34ee2af1e5493d3651d3f58653a29f3d51b727eb4dd2728acf3344d3' 
  AND token = 'leojbJP9sudJiGldoaxxjeSyB2mLlzb4Ll+rA2dZtps=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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