SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd2b61923da07580126882c0e82c057aba1cf3bca2892f944526e294d06b81565' 
  AND token = 'rMcMi6SxeMQP8+tCPdK/bBVhOApD9k/ylfwbWVwT4jw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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