SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '21886c64aabafa7ebdb1cb663915f546fcccf805d2fe33c7dc961fdfde055a8f' 
  AND token = 'hYh2pBA5886SgR+2XjGgvqTFq8oHLQBpzE1LKnz4k9w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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