SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2e7f7adf70bae25a7c7dfd45d8e181735b390effdf8995450b51cbd04d46325d' 
  AND token = '7hjCpiovZBdrbV24zmkrDqWYvQJPJbYeJYuXkClmHaM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00054

JSON explain

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