SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4cb82b622866f7c109e12f6203daa5da05fcddafd880d8f0ac18596652deae64' 
  AND token = 'Gx0igf169SUW5YhfwJkAT9WPkxGtebT7lCnrtKZd2p8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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