SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e619b1cc815098f36f1bbeadff8f015ee637b2ffbed58f1c8ae5fdb1b965f648' 
  AND token = 'UedJjlSR8rfSf+uqNhacKQ3H5KGTjkVDR+B9y/6KWQ0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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