SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e9b7bd3ec0d9d93a75050a001f22497cc9624b0f43be56aa55e15e4a46da3700' 
  AND token = 'J7kqt0pEK0nIbguRWn4+mFvhbtsCFeKZkJKkxerqxLo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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