SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a0735575b109c4e3c7c87a66a73834a569dc0c327659f54d8734dd4c02ff5ddd' 
  AND token = 'iAiGzdQs4C7wjaX2DYSgqFM/uwMjIG/HgqPlW74QJco=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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