SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '74e859e1856095734b64e6cf02b1837d0358a836b7f506493be6db3d20399881' 
  AND token = 'hmPSmjSuuUGBzOfgByFTKXkpRVizS/n3ITSb4OcWEBs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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