SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'db742930a151f0040ea5f0393804683271061595874ce68f786fe7d2777aa3a7' 
  AND token = 'YO9RYqpVjXCOgcMMkcXRuYAqvGYvWJhZ9/FxGyl1jrw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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