SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '543afca08ce908179dc791143225b7c5a6e6b11cc65989f2e64bd3e319778983' 
  AND token = 'YWE6Vf5O2GLJ1s6hVUbqUrKf3pujqtOxB+2LvJizbro=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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