SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dd3f06111f2566aff4d303911d586496cf36c5d5fe919795a76c78b9ed250b9b' 
  AND token = 'PXBDZrxIHR/ML/Np+2M0vL6K0ylv0TQiNSxtQG/5i4w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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