SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aec399a0d32a5ef27e67946d10b8984cb2f3cb77e9812e621101cedae7a56658' 
  AND token = 'dXYglLGkGOm0crDht5NhwEW+AsqKpByj/JKa29vNzcY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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