SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4689b371ea58d5f300a77d3023548d9f0920ae2dad98344a129576e0be951513' 
  AND token = 'blygKIj/Cx1i9z8xs6qDYlPDsZQaeHKeB6w8SYy5iic=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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