SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b86ac3244a7050565d6a4c7a89fb5c3eedcc68b32a49727284943f27b83827c0' 
  AND token = 'dxVwe2mzHSVaMdalAelUUlyd3ZXLKc2l803wwuZnw9Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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