SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '864571e1816804d00a5858ee4f22fb1ae527dbc55439fce2f63f6aa208751551' 
  AND token = 'MjnWDLvRY1Y4pNsmohV9ZKaDSYCewuG7fH5v7lmH138=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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