SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1dcbaebc3356f010966f0c9f919932e784ab64346177fe46c0d548b5b967cc58' 
  AND token = '2h08UspzRXNWNJoWTQzqBd3QUTScqBfbu1MQWvlSX94=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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