SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8f8d8a5c681d4e999545d7e681843d3b690814e71f583a4ff74b46e0631ae797' 
  AND token = 'cJyCiNvZj6WbjP7m6qLiFUx0PPvr7/0ctnmxATBXDno=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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