SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5bfde7c881509499bdfb1417f4135164c5c7f4ba1bd043bfe845d9404d1e062e' 
  AND token = 'Wc5AQhESvuqMgokXkNOEl1v9aFb81T7qnaGmFOED1qM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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