SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '07b5c36c9d0435efaf0a72db4b6316ffa79064d6b913540a24b74d583cc164ea' 
  AND token = 'RNbjPUv5yJuQKtGxtGrsWGGNTDSgIsC1CQv/HzSBZZE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00078

JSON explain

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