SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '873e60aa9a0c2985b6b8a37ccbf47bc99e2e7ed943e6f6cdf1af6896ed8e8a9a' 
  AND token = 'rpZ1wfswPbhGcuCmQUoVIfvfBsiBdHT3ttVWcrzAJJw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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