SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '64e4430ef779fb58c7ca20a0793996e364190b1be6cac587e55991b20c629334' 
  AND token = 'eps0n5wL5UUBW7RqTMxs9qEfos5YX2jlQtftPqBJoQ4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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