SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '56ed6c58f24c9f21946f775649ef1b437a971d1bfc838610bad64b227d80fa83' 
  AND token = 'AmqZlXqRUWbO/0vLc++5WbV0stjOlQYSfj9UCMVzsrY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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