SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '72b609682cbef339d1ea85ab251d1bf8fa3682bc9bad03093b37094acdcc21d2' 
  AND token = 'fGtA491+9jzRIG8sST7HcOgg9YcB9Z1tkFYovW34MsA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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