SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bf83fe75a4d039ffa47786426aea6341589495b429893542bd7c20422535919f' 
  AND token = 'SCVvj+HbG+VCpp7vthQQCogOWMf+1Q9iUuop7jxrHJY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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