SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '932dcc5dde199dce21d3567b8dff1bcc08680d6138109ec3d1a5f2cec9211379' 
  AND token = 'QB47bNq8aJqftWYZCRtTvlN1lom9gPVGcuKCo8yWX6U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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