SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '423e5d166f0656ae997203280e658610cf3137e2314e492eee1a61fc83bc8b1f' 
  AND token = 'jC+vopKJaLr4TGwH/qvOxBbPF7Rq9EwPRWv3OGYt/Rk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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