SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '62d8886ceb6292a45f65b5f36c26de3805ddd2886de0e639b8ed1c77f634e345' 
  AND token = 'K4N0VTimuaohW6BpYXqOOVqjMXEyRpr+1cnRwVlAqYg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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