SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8fbda7e7383fe3f061e5dc0636a6c38528a422093629327edc44cb00425e63b5' 
  AND token = 'vlpGQ3esbdTSvdc8pCUYzo3uKnwZa6RICxmjT2/xpQk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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