SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3987a4600c8d7583d5a46b8eafd32d14961fa59b5917b953549510b1357adde7' 
  AND token = 'eWLHAUwlQJkYGjstuvydFouNvxaliRKrCzhEgLvLKd8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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