SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '53884c1b977610d6969bd33267851d51bd2e632eff1ed1a8dd4d9b9b4abc1093' 
  AND token = 'HFnehhzK7pQq60Slq/ODdYm80GKwToXfvAxsKtJPAHA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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