SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '59e8aea453f94860ce8bad69938442e21eba149cb40c3766a20db2837d53ea8c' 
  AND token = 'U67kn8H7g2t32PDx8lCVymRkF7TdnRfj1uUwR1UY0Q8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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