SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a49a38a68cc1ec99e746eb60350afe459532000c0ce46aa28d13100865b32280' 
  AND token = '4qnrPfus6taBLmEpR1YFeZehD0evdo64V+ESJjBFwE4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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