SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0be83570bd0e9ef61ffb064781b0f0f20d16f0d7f87cd015762b18a7244b149f' 
  AND token = 'xjRUSBEvYY6uGxOc7KGJ9zi7nyIRvKYHmhD9aHAoUls=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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