SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '28986481a84472454ae4e682bb006253f7444d58fdb0fcf9b6fd2c2f9e4573ee' 
  AND token = 'S50nMsW+FTFkthHwSnWJKPMMfScUXpkSIyGqpO01njI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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