SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2b50dcfd3ef37daa895aeb82b7e2e5d67e55220e04d781884dafeeb582b91acc' 
  AND token = 's8QwsvfyiThO7K8/BX24SxuAfIaKs6/sXVnps6bwLNk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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