SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'caea0d7188829f240e62569e2658be5213a5f71f73e5ae08779269b74c2b2f0c' 
  AND token = 'DsLIOdKa/dhQA9Y6q3otc9JFNH/asStQrUVGiGvUefc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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