SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b02e2b5a3e1ca1f03648e9b89366402101eb178770ce16e24d05f60d0a33aa50' 
  AND token = 'LKslxOSPumHupCiyqhwzVSJk8h+uuQG3evidFOyVMzY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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