SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e3ae44d03f6dc1e75b80831279ec21dfda31685839dd42b689f973fbc4dce697' 
  AND token = 'teJuNwihP+B8SJCgYGMuFdy4UZp0MVviO3QKIfL5Vgk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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