SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9cd036c6a591f74c6586b413653b1e75df8fd4629ba594d7962473f321ca5c67' 
  AND token = 'WDWWnCZEIAJ7vg4LNBojpYrGBoV0Lv8KdGZTUUtWidA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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