SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'add5db7d37e55e78889696c284b57c4ef58c4c17676ba357b68e65cb45dcae1a' 
  AND token = 'jWMtRCBshxsPSnflrsZ3fQPFCj7N08DsaWz0zn26J2s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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