SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e54ea17c3340a08a3f5063294be983029d08820c285884305ee743534c42816b' 
  AND token = 'MOzREPxHSLETiR55pH1h1fMjouWOxqzzf8bLWZh1xkc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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